This application relates to plastic molding strips and, more particularly, to plastic molding strips for automotive vehicles.
It is well-known to use molding strips on the surfaces of automobiles. Such strips serve many practical purposes, such as covering joints that would otherwise be unsightly, weather-stripping the interconnections between the metal body and glass areas, and providing protection to the body and the edges of doors when there may be bumping or scraping between the edge of a door on one vehicle and the body of another vehicle. Molding strips can also be used for decorative purposes.
Such moldings have taken many forms, depending to some extent on the use of the strip and the method of attachment of the strip to the body of the vehicle. One type of such molding includes a resilient base having a substantially C-shaped cross section having inwardly directed flanges. In mounting this type of strip, the flanges may be spread apart against the bias of the resilience and allowed to snap into position behind the edges of an elongated support member.
In one type of such moldings soft vinyl chloride is adhered to a strip of cold rolled carbon steel. As shown in FIG. 1, a thin layer of the vinyl chloride is adhered to the inner surfaces and the flange portion of the C-shaped steel strip as an interface with the metallic surfaces of the vehicle body and the molding support to which the molding strip is attached. It is also known to embed the C-shaped carbon steel strip in a soft plastic by injection molding of the soft plastic about the steel strip.
Molding strips prepared either by adhering the soft vinyl chloride to the cold rolled carbon steel strip or by injection molding of the vinyl chloride on the steel strip provide a good appearance and sufficient strength for protection of the vehicle and for remaining firmly attached to the support. Unfortunately, however, the thin layer of soft vinyl chloride on the inner surfaces of the steel strip tends to wear through after long periods of use, and the exposed cold rolled carbon steel strip subsequently rusts. The thin layer of vinyl chloride wears through more quickly, of course, if the injection molding process is incompletely carried out or other errors in the process of fabricating the molding strip leave the inner layer of vinyl chloride thinner than was intended.